Data centers have been predominantly applied by enterprises in information technology deployment. Cloud computing networks have been widely deployed for the data centers, and virtualization including server virtualization, storage virtualization, network virtualization, etc., has almost become an underlying technology in the cloud computing networks. Services and resources of the cloud computing networks are shared by a number of tenants in the virtualized environment. Taking a public cloud computing network as an example, an application system designed by a cloud service provider will be adapted to be accessed by a number of tenants in the same environment. Virtualized resources of the different tenants can be separated and isolated from each other to thereby better guarantee the privacy and the security of data of the tenants.